Nasal polyps yield viable stem cells for regenerative medicine

Researchers at Rasht, Guilan, Iran, have demonstrated that mesenchymal stem cells (MSCs) can be successfully isolated from human nasal polyps and exhibit robust multi-lineage differentiation capabilities comparable to those derived from healthy olfactory mucosa. Published in BMC Molecular and Cell Biology, this comparative study provides evidence that nasal polyps, often discarded as surgical biowaste, represent a viable and accessible source of adult stem cells for potential regenerative medicine applications. The study focused on isolating and characterizing these cells, specifically evaluating their proliferation rates and their capacity to differentiate into osteoblasts, adipocytes, and neurons. By comparing nasal polyp-derived MSCs (NP-MSCs) with olfactory mucosa-derived MSCs (OM-MSCs), the team aimed to clarify the biological potential of cells originating from chronically inflamed tissue versus healthy neuroepithelial tissue.

The research involved the collection of 16 human tissue samples, comprising both nasal polyps and olfactory mucosa, from candidates undergoing Functional Endoscopic Sinus Surgery. Informed consent was obtained from all participants, and samples were processed under sterile conditions to ensure the integrity of the cell cultures. Nasal polyps were identified macroscopically and separated using grasping tools, while olfactory mucosa samples were collected from a specific region superior and medial to the anterior attachment of the middle turbinate. Both tissue types were subjected to enzymatic digestion to release the stem cells, which were then cultured in specialized media to allow for expansion and characterization. This methodological approach allowed for a direct comparison of the biological properties of MSCs from two distinct nasal tissue origins.

Upon isolation, both NP-MSCs and OM-MSCs displayed a flattened, elongated, spindle-shaped, and fibroblast-like morphology under inverted light microscopy. A notable temporal difference was observed in the initial outgrowth of the cells from the tissue fragments. Cells derived from nasal polyp tissue began to sprout approximately three days earlier than those from olfactory mucosa tissue, which started to emerge on the seventh day of culture.

Flow cytometry analysis was conducted to confirm the immunophenotypic profile of the isolated cells in accordance with the guidelines of the International Society for Cellular Therapy. Both NP-MSCs and OM-MSCs exhibited positive expression for the characteristic mesenchymal markers CD44, CD73, CD90, and CD105. Conversely, the cells did not express hematopoietic lineage markers, including CD14, CD34, CD45, and HLA-DR. This specific marker expression pattern is critical for identifying true mesenchymal stem cells and distinguishing them from other cell types that may be present in the tissue. The qualitative confirmation of these markers indicates that the isolated populations are indeed MSCs, possessing the surface antigen profile required for their classification in regenerative medicine contexts.

The study further evaluated the tri-lineage differentiation potential of both cell types, testing their ability to differentiate into osteoblasts, adipocytes, and neurons. Osteogenic differentiation was confirmed in both NP-MSCs and OM-MSCs after 21 days of induction in osteogenic medium, as evidenced by Alizarin Red staining. Interestingly, initial signs of osteoblastic differentiation, such as the formation of cell aggregates, were observed on day 7 in NP-MSCs, whereas OM-MSCs showed these signs around day 10. This suggests that NP-MSCs may have a slightly faster response to osteogenic cues. Adipogenic differentiation was also confirmed in both groups after 21 days, verified by Oil Red staining, with initial lipid droplets appearing after 4 days in NP-MSCs and 7 days in OM-MSCs. These findings demonstrate that both cell sources retain the fundamental capacity to differentiate into bone and fat lineages.

Neurogenic differentiation presented a more distinct contrast between the two cell types. After 21 days of induction with retinoic acid, both NP-MSCs and OM-MSCs produced neuron-like cells with visible elongated processes. However, the degree of neurogenesis was significantly higher in OM-MSCs compared to NP-MSCs. Initial indices of neuronal differentiation were observed on day 5 in OM-MSCs, but not until day 9 in NP-MSCs. This disparity suggests that the olfactory mucosa, a tissue with inherent neurogenic activity, provides a microenvironment that better supports neural differentiation pathways. The significantly higher neural differentiation potential of OM-MSCs may be attributed to their origin in a neuroepithelial tissue rich in neural cues, whereas the chronically inflamed environment of nasal polyps may restrict neurogenic potential while promoting other repair functions.

Proliferation rates were assessed using the Cell Counting Kit-8 (CCK-8) assay at 24, 48, and 72 hours. Both NP-MSCs and OM-MSCs exhibited high viability and proliferation rates, which is essential for their utility in cell-based therapies where large numbers of cells are often required. However, the proliferation rate of OM-MSCs was significantly higher than that of NP-MSCs, particularly after 72 hours, with a p-value of less than 0.001. This finding indicates that while nasal polyps can yield viable stem cells, the healthy olfactory mucosa provides a more robust source for rapid cell expansion. The difference in proliferation rates may reflect the distinct biological states of the tissues, with the inflamed polyp tissue potentially exhibiting different growth dynamics compared to the healthy, self-renewing olfactory mucosa.

The study highlights the potential of nasal polyps as a novel source of MSCs, particularly given that these tissues are frequently removed during surgeries and discarded as biowaste. Utilizing such biowaste aligns with the growing interest in sustainable and accessible sources of stem cells for regenerative medicine. While OM-MSCs showed superior proliferation and neurogenic differentiation, NP-MSCs demonstrated comparable osteogenic and adipogenic capabilities and an earlier initial outgrowth. The accessibility of nasal polyps, which are common in patients undergoing sinus surgery, makes them an attractive candidate for future clinical applications.

Limitations of the study include the relatively small sample size of 16 human tissues and the qualitative nature of the flow cytometry analysis, which confirmed the presence or absence of markers rather than measuring their exact expression levels. Furthermore, the differentiation assays were conducted in vitro, and the in vivo efficacy and safety of these cells in human patients remain to be established. The distinct behaviors of NP-MSCs and OM-MSCs likely reflect their respective tissue origins, with the inflamed environment of the polyp potentially altering the functional properties of the stem cells. Future research is necessary to standardize the isolation and expansion protocols for NP-MSCs and to evaluate their therapeutic potential in pre-clinical and clinical settings.

In conclusion, this study provides compelling evidence that mesenchymal stem cells can be isolated from nasal polyps and possess significant multi-lineage differentiation potential. While OM-MSCs outperform NP-MSCs in proliferation and neurogenic differentiation, NP-MSCs offer a viable and accessible source of stem cells from surgical biowaste. The findings suggest that nasal polyps may play a role in the pathogenesis of nasal polyposis through the presence of these stem cells, and their utilization could contribute to the field of regenerative medicine. Further pre-clinical and clinical studies are required to assess the therapeutic roles of these cells and to determine their safety and efficacy in treating various conditions, including nasal polyposis and other degenerative diseases.

Subject of Research: Comparative analysis of mesenchymal stem cell isolation and differentiation from nasal polyps and olfactory mucosa

Article Title: Isolation and characterization of mesenchymal stem cells from nasal polyps and olfactory mucosa: a comparative analysis of proliferation and multi-lineage differentiation capacity

Article References: Khosravi, N., Pourmohammadi-Bejarpasi, Z., Roudkenar, M. H., Abed, S., Leyli, E. K., & Nemati, S. (2026). Isolation and characterization of mesenchymal stem cells from nasal polyps and olfactory mucosa: a comparative analysis of proliferation and multi-lineage differentiation capacity. BMC Molecular and Cell Biology, 27(1), Article 9. https://doi.org/10.1186/s12860-026-00564-0

Image Credits: AI Generated

DOI: 10.1186/s12860-026-00564-0

Keywords: mesenchymal stem cells, nasal polyps, olfactory mucosa, regenerative medicine, cell differentiation, biowaste, proliferation, flow cytometry, Isolation, characterization, mesenchymal, stem